CMC Cardiac Diagnostics & Imaging Flashcards
6 cards from real CMC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CMC Cardiac Diagnostics & Imaging flashcards as text
What does the PR interval on an ECG represent?
Answer: Conduction time from atrial depolarization through the AV node to ventricular activation
The PR interval reflects total conduction time from SA node firing through the AV node and His-Purkinje system to ventricular activation.
ST elevation in ECG leads II, III, and aVF is most consistent with infarction of which cardiac territory?
Answer: Inferior wall (RCA territory)
Leads II, III, and aVF are inferior leads; ST elevation in these leads indicates inferior STEMI, usually from RCA occlusion.
A corrected QT interval (QTc) greater than 500ms on ECG significantly increases the risk of which arrhythmia?
Answer: Torsades de Pointes
QTc >500ms indicates severe repolarization prolongation, greatly increasing the risk of Torsades de Pointes and sudden cardiac death.
Which ECG change is one of the earliest and most characteristic findings in hyperkalemia?
Answer: Peaked, tall, narrow T waves
Peaked T waves are the earliest ECG sign of hyperkalemia and result from accelerated ventricular repolarization.
Why is new left bundle branch block (LBBB) in a patient with chest pain clinically significant?
Answer: New LBBB may be a STEMI equivalent requiring emergent catheterization
New LBBB with ischemic symptoms meets Sgarbossa criteria and should be treated with the same urgency as ST-elevation MI.
Which arrhythmia produces characteristic 'sawtooth' flutter waves at approximately 300 beats per minute on ECG?
Answer: Atrial flutter
Atrial flutter produces regular sawtooth-pattern flutter waves at ~300 bpm due to a macro-reentrant circuit in the right atrium.